Constipation is a common symptom affecting between 2 percent and 27 percent of the population in Western countries. In the United States, it results in more than 2.5 million visits to physicians, 92,000 hospitalizations, and laxative sales of several hundred million dollars a year. The use of a device to electrically stimulate smooth muscle proves particularly useful in clinical applications associated with the gastrointestinal tract. Specifically, electrical stimulation has been shown to be effective in the treatment of indications including gastroparesis and obesity and more recently, chronic constipation. The technology surrounding smooth muscle stimulation devices has not been optimized. This can primarily be attributed to a gap in knowledge and research surrounding the response of smooth muscle to stimulation with various electrical parameters. The specific aim of our Phase I project was to experimentally determine the optimal electrical pulse waveform type and pulse duration for the energy efficient stimulation of smooth muscle. In summary, the results show an average energy savings of 44% when using truncated exponential biphasic waveforms with pre- measured charge transfer as compared to using traditional rectangular constant current pulses. The objective of this phase II proposal is to design, build, and test an energy efficient implantable smooth muscle stimulation device for the treatment of chronic constipation. The device will deliver the optimal electrical pulse parameters and pulse shape for maximum energy efficiency as determined in the Phase I research. A series of colonic transit studies will then be performed in canine subjects to demonstrate the safety and efficacy of the device. The long-term goal of this research is to design, build, and commercialize a fully implantable, FDA approved, energy efficient smooth muscle electrical stimulation device to treat chronic constipation. PUBLIC HEALTH RELEVANCE: Chronic constipation causes a decreased quality of life in up to 27% of the U.S. population, and is associated with 2.5 million visits to doctors and 92,000 hospitalizations annually. Most pharmaceutical treatments (i.e., laxatives) are not effective in treating chronic constipation. Availability of the proposed energy efficient Colon Motility Pacer (CMP-1) will help to increase the quality of life associated with chronic constipation.